Dyn has 500 managed DNS users and partners using their APIs, growing from 7.3 million monthly API requests in January 2012 to 38.1 million API requests in September 2013, that is a 420% growth over 20 months.

In their data they split out who is using SOAP vs REST APIs, with only 3.3% of their total API requests being SOAP, with almost no growth in same time period, compared to the 420% growth in REST usage.

I don't think the data is particularly noteworthy, it represents what we already know about the space and see reflected in other charts. What I think is noteworthy is Dyn sharing the data. You don't see many API publishers sharing their numbers, and its something I'd like to see more of.